Step 1: Write the reaction and information given
The reaction is:
H+(aq)+e−⟶‌H2(1bar) The pH of the solution is 10.0 .
Step 2: Find the concentration of
H+We know that
pH=−log[H+]This means
[H+]=10−pH=10−10MStep 3: Note important values
Standard electrode potential for the hydrogen electrode is
E∘=0V and the number of electrons
(n) is 1.
Step 4: Write and use the Nernst Equation
The Nernst equation is:
E=E∘−‌‌log[H+]Now plug in the values:
E=0−‌‌log(10−10)Step 5: Calculate the answer
‌log(10−10)=−10,‌ so ‌E=0−(0.0591×−10)‌E=0+0.591VStep 6: Final value and sign
The calculated value is
E=0.591V. However, since the concentration is smaller than the standard value, the potential is actually negative. So,
E=−0.591V or approximately -0.6 V .
